1993 Ford Mustang Notchback - Captain Hook - PHR Project Car

Reducing flex in the control arm brackets can put additional stress on the boltholes and cause them to elongate. To prevent them from becoming egg-shaped, Buck welded washers to both sides of each bolthole.

Unlike the upper control arm brackets, the lower control arms push their anchor points into the body. Under heavy stress, this area will cave in and buckle. To combat this, Buck not only beefs up the factory spot welds, but also welds in torque box reinforcement plates provided by Competition Engineering.

Much stronger and lighter than the factory pieces, Competition Engineering's upper control arms are built from mild steel. Their spherical bearings won't do much for NVH, but they dramatically reduce deflection and binding compared to the stock rubber bushings. The length of the arms can also be altered to fine-tune the pinion angle.

Competition Engineering's coilover conversion kit moves the spring mounting point from the lower control arm to the rear-end housing. This enables brisk ride height changes, and the single-adjustable shocks feature 12 different stiffness settings. Some sanctioning bodies forbid relocating the springs, but since Project Fox isn't being built to compete in a specific class, this arrangement is stock enough for us.

Lowering the ride height adversely affects lower control arm geometry and compromises traction. Competition Engineering's setup features bolt-in brackets with three adjustment points that allow altering the instant center. The bars are finished in satin black, and the brackets are zinc-plated for durability.

One of the most important links in the entire rear suspension is the heavy-duty drag sway bar. It consists of a chrome-moly torsion tube, 6061-T6 billet aluminum swing arms, and adjustable endlinks. Like a street or road race sway bar, a drag sway bar controls the weight transfer of a car from side to side. Unlike a road race sway bar, however, a drag unit is used to preload the suspension. Not only does this prevent excessive body twisting at launch, it also drives the rear end into the ground as weight transfers rearward at launch for maximum traction. As a result, a drag sway bar has no free-play whatsoever, and is far too stiff for a road race application.

After spraying down the exposed bare metal with undercoating, the coilovers were bolted into position. They attach to the rear end and body at the factory shock mounting locations using adapters provided in the kit.

The Competition Engineering lower control arm brackets mount to the rear-end housing using the stock bracket and boltholes. For added insurance, Buck chose to weld them as well. MIG welding is more forgiving when attaching two pieces of metal with a large gap between them. To help locate the bracket, the lower control arm was installed before welding it all together.

The angle of the lower control arms determines the instant center. Pointing them farther upward moves the instant center rearward, which transfers weight from front to back more quickly. The ideal setup is a compromise, however, since this also unloads the rear tires more quickly as a car progresses down the track.